Food, glorious food!
Even in the dingy back-alley orphanage of Dickensian London, this refrain from the opening song of the musical "Oliver!" has the power to lift the hungry and penniless orphans from their depression into ecstatic song.
But even for the rest of us, food can often change our frame of mind.
Hundreds of expert answers to common questions on mind and mood can be found at the ABC News OnCall+ Mind and Mood section, here.
"Food really does have a lot of power," said Bonnie Taub-Dix, a registered dietician and spokesperson for the American Dietetic Association. "Use it properly and have a well-balanced diet and you really can improve your mood."
Studies have shown that some foods, like turkey, whole grain breads, and sugary snacks, have definite effects on the brain, raising and lowering mood-altering chemicals.
"Not only does your food affect your mood, your mood affects the food you'll choose," Taub-Dix said. "Unfortunately, the average consumer isn't eating a healthy enough diet, let alone a diet that will put them in a good mood."
According to the National Institutes of Health, 20.9 million Americans suffer from mood disorders and 14.8 million experience depression.
These rising rates of depression and other mood disorders parallels the rise of obesity in the U.S.
Since the mid-1970s, the prevalence of overweight and obese people, aged 20-74, increased from 15 percent to 32.9 percent, according to the Centers for Disease Control and Prevention. More than one-third of U.S. adults — over 72 million people — were obese in 2005.
Though no studies show that mood disorders and increased obesity are directly related, many agree that there is some correlation.
"It is hard to establish cause and effect," said Robert Thayer, a professor of psychology at California State University at Long Beach. "But it's not by chance that stress has been going up and depression has been going up and obesity is going up."
But Lona Sandon, a registered dietician and spokesperson for the American Dietetic Association, points out that distinguishing between a bad mood and a clinical disorder is important.
"Attempting to treat clinical depression on your own through food is not a good idea," she said. "Also, treating a bad mood with foods can leave you with unwanted excess weight and negative feelings about food."
The most effective way to stabilize mood is to eat a balanced diet of protein, carbohydrates, fruits and vegetables, and limit sugar, fat, and alcohol. Coupled with exercise, this regime will keep levels of endorphins, the brain's feel-good chemicals, steady.
But some still swear by the curative effects of an intensely healthy diet.
"I've seen people make dramatic improvements in depression and anxiety within a week of making some simple dietary changes," said Trudy Scott, a nutritionist and spokesperson for the National Association of Nutrition Professionals.
Although their efficacy varies from person to person, the following are some foods that are known to affect your mood.
Whether it's baked, broiled or raw sashimi, eating salmon and other oily fish like mackerel and sardines can bring a smile to your face.